Histone deacetylases (HDACs) are enzymes that regulate epigenetics by removal of acetyl groups from the lysine residues of proteins, including histones. The family of zinc-dependent histone deacetylases has been variously implicated in different disease states, including cancer, neurodegeneration, inflammation, and autoimmune, infectious, metabolic, hematologic, and cardiovascular dysfunctions. Three broad spectrum HDAC inhibitors have been approved for the treatment of cancer: vorinostat (cutaneous T cell lymphoma and multiple myeloma), romidepsin (peripheral T-cell lymphoma), and belinostat (peripheral T-cell lymphoma). However, there continues to be a need for an improved efficacy-safety profile and for efficacy against other types of cancer. While the potential for HDAC inhibitors as treatment for non-oncology indications has been recognized, one has yet to be approved.
As a regulator of the common post-translational modification of protein acetylation, the zinc-dependent histone deacetylases play a critical role in diverse cellular processes. Inhibitors of histone deacetylases have been approved as treatment for cutaneous T cell lymphoma and peripheral T-cell lymphoma. The potential remains for HDAC inhibition as a therapy for other types of cancer. For non-oncology therapies, HDAC inhibition will provide a novel pharmacological strategy.